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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/mips/sibyte/sb1250/time.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/mips/sibyte/sb1250/time.c')
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1 files changed, 136 insertions, 0 deletions
diff --git a/arch/mips/sibyte/sb1250/time.c b/arch/mips/sibyte/sb1250/time.c
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1/*
2 * Copyright (C) 2000, 2001 Broadcom Corporation
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version 2
7 * of the License, or (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 */
18
19/*
20 * These are routines to set up and handle interrupts from the
21 * sb1250 general purpose timer 0. We're using the timer as a
22 * system clock, so we set it up to run at 100 Hz. On every
23 * interrupt, we update our idea of what the time of day is,
24 * then call do_timer() in the architecture-independent kernel
25 * code to do general bookkeeping (e.g. update jiffies, run
26 * bottom halves, etc.)
27 */
28#include <linux/config.h>
29#include <linux/interrupt.h>
30#include <linux/sched.h>
31#include <linux/spinlock.h>
32#include <linux/kernel_stat.h>
33
34#include <asm/irq.h>
35#include <asm/ptrace.h>
36#include <asm/addrspace.h>
37#include <asm/time.h>
38#include <asm/io.h>
39
40#include <asm/sibyte/sb1250.h>
41#include <asm/sibyte/sb1250_regs.h>
42#include <asm/sibyte/sb1250_int.h>
43#include <asm/sibyte/sb1250_scd.h>
44
45
46#define IMR_IP2_VAL K_INT_MAP_I0
47#define IMR_IP3_VAL K_INT_MAP_I1
48#define IMR_IP4_VAL K_INT_MAP_I2
49
50extern int sb1250_steal_irq(int irq);
51
52void sb1250_time_init(void)
53{
54 int cpu = smp_processor_id();
55 int irq = K_INT_TIMER_0+cpu;
56
57 /* Only have 4 general purpose timers */
58 if (cpu > 3) {
59 BUG();
60 }
61
62 if (!cpu) {
63 /* Use our own gettimeoffset() routine */
64 do_gettimeoffset = sb1250_gettimeoffset;
65 }
66
67 sb1250_mask_irq(cpu, irq);
68
69 /* Map the timer interrupt to ip[4] of this cpu */
70 bus_writeq(IMR_IP4_VAL,
71 IOADDR(A_IMR_REGISTER(cpu, R_IMR_INTERRUPT_MAP_BASE) +
72 (irq << 3)));
73
74 /* the general purpose timer ticks at 1 Mhz independent if the rest of the system */
75 /* Disable the timer and set up the count */
76 bus_writeq(0, IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
77#ifdef CONFIG_SIMULATION
78 bus_writeq(50000 / HZ,
79 IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT)));
80#else
81 bus_writeq(1000000/HZ,
82 IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT)));
83#endif
84
85 /* Set the timer running */
86 bus_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
87 IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
88
89 sb1250_unmask_irq(cpu, irq);
90 sb1250_steal_irq(irq);
91 /*
92 * This interrupt is "special" in that it doesn't use the request_irq
93 * way to hook the irq line. The timer interrupt is initialized early
94 * enough to make this a major pain, and it's also firing enough to
95 * warrant a bit of special case code. sb1250_timer_interrupt is
96 * called directly from irq_handler.S when IP[4] is set during an
97 * interrupt
98 */
99}
100
101void sb1250_timer_interrupt(struct pt_regs *regs)
102{
103 extern asmlinkage void ll_local_timer_interrupt(int irq, struct pt_regs *regs);
104 int cpu = smp_processor_id();
105 int irq = K_INT_TIMER_0 + cpu;
106
107 /* Reset the timer */
108 __bus_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
109 IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
110
111 /*
112 * CPU 0 handles the global timer interrupt job
113 */
114 if (cpu == 0) {
115 ll_timer_interrupt(irq, regs);
116 }
117
118 /*
119 * every CPU should do profiling and process accouting
120 */
121 ll_local_timer_interrupt(irq, regs);
122}
123
124/*
125 * We use our own do_gettimeoffset() instead of the generic one,
126 * because the generic one does not work for SMP case.
127 * In addition, since we use general timer 0 for system time,
128 * we can get accurate intra-jiffy offset without calibration.
129 */
130unsigned long sb1250_gettimeoffset(void)
131{
132 unsigned long count =
133 bus_readq(IOADDR(A_SCD_TIMER_REGISTER(0, R_SCD_TIMER_CNT)));
134
135 return 1000000/HZ - count;
136 }